ThermoBar’s electrically heated water troughs are equipped with a thermostat that controls how warm the water gets. When the water is warm enough, at about 17 degrees, it turns off. This means that the water temperature never gets too high, at the same time as it keeps energy use at a minimum. Insulation is also important for saving energy. ThermoBar’s toughs are made from food-grade polyethylene and they are insulated with styrofoam that has a U-value of about 0.04 (watt/square metre and kelvin). The walls are 3-5cm thick.
How much energy is needed to warm up a ThermoBar 80 with 80 litres of water from 2 to 17 degrees?
Answer: To raise the water temperature, the amount of energy needed depends on the temperature increase ∆T, the volume of what is going to be heated (the water) and water’s specific heat capacity which is 4.18kj/(kg K) (which is the same as 1.16 * 10-3 kWh). The amount of energy needed can be calculated using the formula Q=mc∆T.
So: Q = 80*1.16*10-3*15 = 1.4 kilowatt hours (kWh)
1.4 kilowatt hours in Sweden currently costs about SEK 1.70.
The water is heated up to 17 degrees, then the thermostat will turn the heating function off.
The following shows how much energy is used by the different models if the water would be constantly heated for 24 hours.
Modell, effect Energy use Electricity cost
of the thermostat (kWh/24hrs) (SEK/24hrs)
Thermobar 30 – 50 watt 1.2 1.40
Thermobar 65 – 75 watt 1.8 1.60
Thermobar 80 – 90 watt 2.2 2.20
Thermobar 140/250 – 150 watt 3.6 3.60
Thermobar 140/250 – 220 watt 5.3 5.30
The electricity cost is calculated to be about SEK 1.20 for green electricity, including taxes.
To make this more easily understood, we can compare a ThermoBar with common household appliances. A fridge or freezer needs 1.5-2.2 kilowatt hours/day and a washing machine uses about the same amount per cycle. This is about the same as a ThermoBar 80 that is on all day. A tumble dryer can use about 5 kilowatt hours each time it is used. If you shower using hot water for 15 minutes you use as much energy as a ThermoBar 250 needs to stay warm for a day.
Another example: Imagine that you drive home at lunchtime to fill up your horses’ water troughs in the winter. If your car uses 0.7 litres of petrol per 10km, then a 10 km round trip uses about 6 kilowatt hours. That is twice or even three times as much energy as you need to warm the water in a ThermoBar for a whole day. The cost of petrol is also much higher than the cost of electricity, plus you are releasing CO2 into the atmosphere.
More comparisons for energy use:
Thermobar 80 that is on for 150 days 300 kWh/yr
Fridge and freezer 900 kWh/år
Shower for 5 minutes/day 1000 kWh/yr
Heat the oven to 250 degrees 0.15 kWh each time
A regular family’s washing 300 kWh/yr
A regular family’s lighting needs 800 kWh/yr
To make your ThermoBar as energy efficient as possible we recommend that you:
• Always use a lid on your ThermoBar when the horses are not in their enclosure.
• Place the ThermoBar in a protected position so it is not exposed to excessive wind chill.